Self-supportable parenteral bottles of synthetic resin are known, and those of various constructions have already been proposed. Such parenteral bottles generally have resting portions bulged downward from the bottom at opposite sides thereof, and a suspender flap downwardly projecting from and hingedly formed on a flat bottom portion between the resting portions in alignment with the bottom center line. The resting portions to be seated and the suspender flap are molded simultaneously with the bottle body by a direct blow molding process. The suspender flap is held upright raised from the bottom when the parenteral bottle is suspended in an inverted position for use, but when the bottle is placed upright on a table or the like, the suspender flap is turned about a hinge at its base end to a folded position and accommodated in a space between the table surface and the bottle bottom to render the bottle self-supportable with good stability.
The bottom of the bottle is prone to deformation due to thermal shrinkage during the molding operation or due to a rise of the internal pressure when the bottle is sterilized by heating with a parenteral solution contained therein. Accordingly, the conventional parenteral bottle has the problem of failing to support itself stably when used in a standing position because the suspender flap can not be stowed completely in a folded position.